In the 1920s Thomas began playing cricket at the age of eleven before joining district club Annandale, which led to her selection for NSW in 1937.
A representative cricketer for ten years, Thomas played for NSW against New Zealand in 1946 and for a joint NSW and Australia XI against England in 1948, before retiring from the game in the late 1950s.
She then became president of the then Australian Women's Cricket Council, where she became a life member.
Known as affectionately 'Auntie Lorna' to many, she became the Team Manager of the Australian women's cricket team in 1960, going on to manage five international teams including four overseas tours.
She retired from her position as manager of the NSW and Australian teams in 1978, before being awarded an MBE for services to cricket and was made a life member of Women's Cricket Australia.
The annual Cricket NSW Women’s City vs Country series is named in honour of Thomas.