Thanks for going the distance, but no luck.
Neither my classical library sidebar nor that of my non-classical library shows "Artists", which, for lack of anything else to blame, I'll attribute to my never having purchased music from the iTunes Music Store; I'll also attribute the other elements that appear on your screen but are missing from mine to the same thing.
My classical library sidebar doesn't show "Albums", but my non-classical library sidebar does, and I've got no idea why.
