Jerome Kern will the be focus of a concert Oct. 23 at Lexington’s National Heritage Museum, 33 Marrett Road. Winchester resident Dan Loschen will lead his group Boston Musical Theater in this revue-style performance, titled “All the Things You Are: The Music of Jerome Kern.”The show will be a tour through the composer’s life, from early hits such as “They Didn’t Believe Me,” to his well-known standards such as “Smoke Gets In Your Eyes, [...]