Even Star Alliance own website says the same thing, as per below. Note how the international flight is only mentioned together with United/US clubs. We now have two sources which to me both quite clearly state that non-UA/US clubs can be accessed with domestic tickets.

http://www.staralliance.com/en/benef...access-policy/

Star Alliance Gold Customers Travelling in Any Class: Customers have access to any Star Alliance member carriers' owned lounges with the Star Alliance Gold logo at the entrance.

• Customer must present proof of Star Alliance Gold level status via a valid frequent flyer program Star Alliance Gold level card or other valid indication of Star Alliance Gold level status
• Customer must also present a boarding pass for travel on a Star Alliance flight departing from the local airport
• Customer is entitled to one guest
• United and US Airways Star Alliance Gold customers may only access the United Clubs and US Airways Clubs within the U.S. when travelling in conjunction with a Star Alliance international flight.