Leslie, you sound much calmer and more composed than many of the rest of us do about this! I am so peeved I cannot see straight!

I've rented apartments in California as well as near Chicago, and in both places the following was a LAW: the landlord must give written notice (24 hrs or 3 days, can't recall which) to enter an apartment for any maintenance that you didn't request. I believe the only time they can come in without written notice is if you have given your notice that you'll be moving out, in which case they can show your apartment pretty much anytime.

Warn that landlord STRONGLY and by registered mail that you'll take him to small claims court for any damages--to poor Graham, to your heating bill, whatever--he causes next! It's inexcusable.