Lonsdale competed in alpine skiing for 16 years. However, she switched sports to freestyle skiing, where she trialled several disciplines: mogul, aerial, and skiercross. She eventually decided to participate in halfpipe skiing. At the 2008 X Games, Lonsdale finished in ninth place in halfpipe, and at the FIS Alpine World Ski Championships 2011 she finished in 11th place. She has won the halfpipe at the British Championships every year from 2003 to 2011.