His short Wikipedia entry is here. It mentions that he was the father of noted musician Constant Lambert (1905-51).
So far as I am concerned, the most distinctive period of Lambert's career was approximately 1905-1910, and the images below are from then. Lambert's style was strong, featuring solid, visible drawing. Faces are usually painted smoothly, but other parts of the same painting are often somewhat blocked in using disciplined, visible brush strokes.