The lounge access for oneworld connect seems quite complicated. But it seems the overall rule is that if you are on a flight where you are ticketed using the flight number that matches your FF program, then you get access. Otherwise you don't.
For example, as a CX member, if you fly on FJ metal, and your ticket is a QF flight number, you won't get lounge access. If you fly on FJ metal, but you bought the CX flight number, then you would get lounge access.
Last edited by sxc; Dec 6, 2018 at 11:38 pm
Reason: Removed ambguity about codeshares