QF is using the BA Terraces lounge for the SYD flight departure. If they are using the AC, it is only for QF codeshares (operated by AA) which leave from the AA terminal and not the international terminal. Maybe they plan to operate the YVR-SFO arrival into the AA terminal, as this will be the only way to be at the AC, but that seems absurd (in the past that was also in the international terminal, and using the BA lounge). There was a time when BA had contracted out their lounge to a non-OW airline during the QF flight time, and QF couldn't use it, but I think this has now been resolved. fwiw, while the BA lounge is disappointing, it is a lot better than the JL or AA lounges.