Originally Posted by
alfiek
.... I was able to use LH Senator lounges ....
OP's questions was about IFL/GF lounges.
IFL/GFL access is
1) you are departing that airport in *A International first class (the third cabin in aircraft that have 3 cabins)
or
2) if one leg ("same day") is in UA GF then you have access to arriving airport UA GFLs also.