Complex sentence: Larkin began his working life in commercial art, advertising design groups and for the book publisher Pearson Longmans, but in 1967 his vocation as a writer made its first appearance when he began writing for music journals and magazines.
Split into simpler sentences: Larkin began his working life in commercial art, advertising design groups and for the book publisher Pearson Longmans. In 1967 his vocation as a writer made its first appearance in the public domain, when he began writing for music journals and magazines.