So you do not have Star Alliance status via SQ and will be crediting to your SQ account but are a current *G via TK?

It may take some explaining to the lounge agents, but yes--if you are Star Alliance Gold and are traveling on any Star Alliance carrier, you are entitled to access Star Alliance Gold lounges on the day of travel. As you suggested, just show them your boarding pass and Gold card (and be prepared to explain your situation), and you should be fine.