She was the Liberal Party member of the New South Wales Legislative Assembly for Sutherland from 1997 to 1999.
Stone was born Lorna Nicholson to parents Alfred and Erla.
In 1974, she joined the Sylvania branch of the Liberal Party, and remained active in the party thereafter, holding various positions including campaign secretary and chairman of the local government executive.
Labor had defeated the Liberal government two years earlier and had hopes of winning the seat, but Stone emerged with an increased majority over Labor candidate Christine Hawkins.
[1] Stone was appointed a Member of the Order of Australia in the 2014 Queen's Birthday Honours in recognition of her "significant service to community health through roles with a range of organisations".