Last year I flew with LX to JFK from ZRH and my booking told me that the flight was operated by Edelweiss. When I pitched up at the gate I saw an A330 in LX colours and with (with what I thought to be) LX crew on board. The C product was also that of LX. When I asked the question, I was told that yes it was an Edelweiss aircraft but on lease to LX. I should imagine that if you are travelling C cabin and can do seat assignment, this will indicate to you what the product will be.