And just for the sake of clarity, passing through immigration does not mark the "start" of Terminal 2. T2 starts somewhere around gate 16-19, but unless you pay extra special attention, it is not really obvious where one ends and the other one starts, as the terminals, especially on airside are properly joint together.

I believe that for your purposes, it is more useful to talk about Schengen and non-Schengen sides of the airport. Your lounge is on the non-Schengen side, exactly where Courmisch said it would be.

And just in case, here is a link to a terminal map...

Now just pay for the lounge access, print out the voucher/receipt you will receive and you should be all set, as by now you have all the info you might possibly need...