Question: When did Randolph Churchill's former wife help form a nonprofit organization?

Context paragraphs:
Winston Churchill (1940–2010): Winston Spencer-Churchill (10 October 1940 – 2 March 2010), generally known as Winston Churchill, was a British Conservative Party politician and a grandson of former Prime Minister Sir Winston Churchill.  During the period of his prominence as a public figure, he was normally referred to as Winston Churchill, MP, in order to distinguish him from his grandfather.  His father Randolph Churchill was also an MP.

Montagu Porch: Montagu Phippen Porch (1877- November 1964) was Winston Churchill's stepfather, although three years his junior.  He was born in 1877 in Glastonbury, a parish of Somerset in the United Kingdom.  He was educated at Magdalene College in Cambridge.  In 1900 he joined the Imperial Yeomanry, which was a Cavalry regiment of the British Army.  In 1906 he joined the Colonial Service and served as an officer until 1919, with the majority of his duties served in Africa.  On June 1, 1918, Porch married Lady Randolph Churchill, mother of Winston Churchill.  There was quite an age difference here as Porch was 42 and Lady Randolph Churchill (Jennie Jerome) was 64.  It was Lady Randolph's third marriage and the first for the younger Porch.  The couple remained married for three years until Lady Randolph Churchill's death in 1921.

American-Russian Cultural Cooperation Foundation: The American-Russian Cultural Cooperation Foundation (ARCCF) is an American nonprofit focused on the promotion of American-Russian cultural dialogue and cooperation.  Founded in 1992 by a group of prominent Americans, including former Missouri Congressman James W. Symington, Pamela Harriman, former Chief of Staff and Tennessee Senator Howard Baker, and businessman Bill Marriott, the nonprofit has organized concerts, exhibitions, galas, and other cultural events that highlight the history of American-Russian cultural interactions.  It is currently headed by Eugene K. Lawson, former US Ambassador to the WTO and founder of the US-Russia Business Council.  Former Soviet cultural attaché Alexander Potemkin has served as the organization's executive director since its creation.  ARCCF is based in Washington, DC.

World Assistance for Cambodia: In 2012, the organization has been renamed World Assistance for Cambodia.  It uses cambodiaschools.com which it jointly operates with its Japanese sister organization Japan Relief for Cambodia.  From the mission statement on its website: "World Assistance for Cambodia (WAfC)/Japan Relief for Cambodia (JRfC) are independent nonprofit organizations dedicated to providing opportunities for the youth and rural poor in Cambodia.  World Assistance for Cambodia is registered in the United States as a 501(c) (3) tax-deductible nonprofit organization.  Within Cambodia, WAfC / JRfC is recognized by the Cambodian government as one nonprofit organization."

Descendants of Winston Churchill: Sir Winston Churchill, son of Lord Randolph Churchill and grandson of John Spencer-Churchill, 7th Duke of Marlborough, was Prime Minister of the United Kingdom between 26 October 1951 – 6 April 1955 and 10 May 1940 – 26 July 1945.  In 1908, Churchill married Clementine Hozier, the daughter of Sir Henry and Lady Blanche Hozier.  By Clementine, Churchill had five children and ten grandchildren, a number of whom are well known in their own right.

Pro Bono Net: Pro Bono Net is a US nonprofit organization based in New York City and San Francisco.  The organization works in close partnership with nonprofit legal aid organizations across the United States and Canada, to increase access to justice for the millions of poor people who face legal problems every year without help from a lawyer.  It does this by (i) supporting the innovative and effective use of technology by the nonprofit legal sector, (ii) increasing participation by volunteers, and (iii) facilitating collaborations among nonprofit legal organizations and advocates working on similar issues or in the same region.  Founded in 1998 with a grant from the Open Society Institute, Pro Bono Net has developed a broad base of support from foundations, law firms, corporate sponsors and nonprofit partners alike, to build web platforms that offer powerful and sophisticated online tools to pro bono and legal aid advocates, and to provide critical legal information and assistance directly to the public.  Its model has been adopted in 30 states and regions, reaching approximately two-thirds of the poverty population and lawyers in the United States.

Lord Randolph Churchill (book): Lord Randolph Churchill was a two-part biography written by Winston Churchill of his father, the Victorian politician Lord Randolph Churchill.  It was first published in 1906.

Lady Randolph Churchill: Lady Randolph Spencer-Churchill, (née Jennie Jerome; 9 January 1854 – 29 June 1921) was an American-born British socialite, the wife of Lord Randolph Churchill and the mother of British Prime Minister Sir Winston Churchill.

Nonprofit organization: A nonprofit organization (also known as a non-business entity) is an organization that has been formed by a group of people in order "to pursue a common not-for-profit goal", that is, to pursue a stated goal without the intention of distributing excess revenue to members or leaders.  A nonprofit organization is often dedicated to furthering a particular social cause or advocating for a particular point of view.  In economic terms, a nonprofit organization uses its surplus revenues to further achieve its purpose or mission, rather than distributing its surplus income to the organization's shareholders (or equivalents) as profit or dividends.  This is known as the non-distribution constraint.  The decision to adopt a nonprofit legal structure is one that will often have taxation implications, particularly where the nonprofit seeks income tax exemption or charitable status.

Pamela Harriman: Pamela Beryl Harriman ("née" Digby; 20 March 1920 – 5 February 1997), also known as Pamela Churchill Harriman, was an English-born American socialite who was married and linked to important and powerful men.  In later life, she became a political activist for the Democratic Party and a diplomat.  She was married three times, her first husband being Randolph Churchill, the son of prime minister Winston Churchill.  Her only child, Winston Churchill, was named after his famous grandfather.

Supporting paragraphs: American-Russian Cultural Cooperation Foundation Pamela Harriman
Answer: 1992