shefgab QRs check-in usually starts three hours prior to departure and often closes one hour before departure. So I would assume this unless it states otherwise on your e-ticket.
Look at
https://www.oneworld.com/ffp/lounge-...eaccess/trv/-1 for the description of the Ruby Arena lounge. do expand the webpage using 'View full details' because there is important information for you there.