Whilst there, she took part in many amateur productions, including plays by local playwrights John Newman-Holden and Tim Bull.
Lonsdale is best known for her portrayal of police officer Emma Watts (née Taylor) on the long-running ITV soap opera Coronation Street.
First appearing in April 2000, her storylines included a long-lasting feud with neighbour Les Battersby and a tempestuous marriage to Curly Watts, with whom she departed Weatherfield in September 2003 upon securing a job promotion.
Next, Lonsdale began appearing as DI Eva Moore in the daytime BBC drama Doctors.
Her other notable credits have included All Quiet on the Preston Front, The Bill, Casualty, Holby City, Joe Maddison's War, This Is England '90, Scott & Bailey, Vera, Our Girl, The Syndicate, and Hollyoaks.