Is that assertion made from personal experience? I ask simply because I can find nothing on the CX or oneworld websites to support it in the case of a LH F -> SH J transit access.

And my "no interlining" comment doesn't apply here, but would if, for example, someone was arriving on BA F and transiting on a separate ticket and PNR to CX J (or Y). CX would no longer regard that as "connecting" from the point of view of baggage handling, so do we have any evidence yet as to whether that still counts as "connecting" from the point of view of lounge access?