Trained early on in music by his mother, Lessing studied violin in Basel with Hansheinz Schneeberger and, over the years, has refined his artistic sensibility through his contact with older composers and musicians such as Zoltán Székely, Berthold Goldschmidt, and Ignace Strasfogel. He is a tireless champion of neglected repertoire, and reintroduced the forgotten violin suites of Johann Paul Westhoff and the violin fantasias of Georg Philipp Telemann to the repertoire. In recognition of his efforts on behalf of little-known composers and works, Lessing was awarded Germany's Johann Wenzel Stamitz Prize in 1999.