Hey, just got to Stockholm Arlanda and tried the lounge and unfortunately the rule is, if you fly Lufthansa, only Senator and above is accepted. Other Star Alliance Gold cards don't get you into the lounge. But a business class ticket does.
Same for Aegean apparently, if you fly Aegean from Stockholm and have Aegean Gold, then you can get into the lounge. But not if you fly Lufthansa and have Aegean gold. Not fun.