As I read it--and I've read the NW, KL and ST site info carefully--Elite Plus members (that's Plats only on NW) can access any SkyTeam member lounge (except dedicated First Class-only lounges) at the airport they're using, on the day of any international SkyTeam flight.

SkyTeam's site has a useful feature called Airport Manager: you select the airports on your itinerary and it shows you all the lounges, along with other info.

It's at http://www.skyteam.com/EN/travelReso...arch/index.jsp