Correct, but changes the meaning.

"Evde oluyorum" is like "I am at home(generally)". It doesn´t mean that you are at home now but you usually stay at home.

"Evde olurum" is the same as above, but it can be also used for future; I think you can also say in English "I am at home tomorrow".

Evde oldum , no there is nothing like that (I don´t know why )

"Evde olurdum" is "I used to be at home".

Wow. Thank You so much dilliduduk !!  That is so helpful!!! 

you are welcome!

Well, it can mean two things; first, as dilliduduk said above, "I used to be home"(you don´t need the "at" there actually) in cases like;

Küçük bir çocukken her gün saat 5´te evde olurdum.

meaning

When I was a little kid, I used to be home at 5 o´clock every day.

however, there is one more possible case;

Manavda durmasaydım, daha erken evde olurdum.

which roughly means,

If I hadn´t stopped for groceries, I would have been home 15 minutes earlier.

hope I could help=)

Ah, pardon=) Türkçe cümleye koymayı unuttum o parçayı=) How silly of me...