MB ChB Manch 1942; MRCS LRCP 1943, FRCS 1949.
Lonsdale was born in Macclesfield on 8 March 1919 (possibly the son of Thomas Lonsdale). He received his medical education at Owens College Manchester and held junior appointments at MRI before being appointed surgical registrar to Royal Manchester Children's Hospital in 1952. Lonsdale was later senior surgical registrar MRI and then at Preston and Chorley Hospital Group, where he became consultant surgeon. Lonsdale was a fellow of MMS.