In the 1901 Directory for Montreal Louis Samuel Clayton is not mentioned. Enclosed are the following names that do appear, however. Perhaps there's a link.
Clayton, Albertfirebrick mgr 2055 St James, St Henri Clayton, Harrymgr21 Victoria Clayton, Herbertfirebrick manufacturer, 16 EadieVille St Paul Clayton, Johnbrickmaker 1013 St Antoine, St Henri Clayton, Mrs S wid. George7 Cote St Paul Rd, Turcot village Clayton, Wm of Montreal Fire Brick & Terra Cotta works,1198 St Antoine, St Henri
These Clayton all seem related. Perhaps Louis Samuel had already left for Toronto in 1901. Good luck