Old news. *A Gold pax can enter the SQ Krisflyer Gold lounge when in Y on a *A flight. Pax in C class on SQ, LH etc can enter (the much better) Silverkris Lounge regardless of status.

LH pax in C regardless of status can enter the LH business lounge. *A Gold pax can enter the Senator lounge. What is the difference ? (except that the Senator lounge is better than the LH Business lounge (but more crowded) whereas SQ has decided to make the Silverkris lounge much better than the Krisflyer Gold lounge).