TK uses the Swissport lounge: http://www.flychicago.com/OHare/EN/A...e-Lounges.aspx
Swissport lounge review

There are also Swiss/Austrian and Scandinavian lounges that you could access as a *A member, but the Scandinavian lounge would be awfully crowded since the TK flight is scheduled right between the two SK flights (one to ARN, one to CPH), and they'd most likely claim there's no room and refer you to the Swissport lounge even if you are *A Gold.
The Swiss/Austrian lounge closes after the Zurich flight leaves at 7pm.

(RJ uses the AF/KLM lounge, so you won't encounter the same lounge when flying TK).