Good Evening everyone!

So, I'm flying UA overseas for the first time in two weeks. I'm flying YHZ-ORD, then ORD-LHR. I'm arranging pick up service from Heathrow to my hotel, however they want to know what terminal I arrive in. On my Itinerary it does not tell me what terminal I'm arriving in.
I went to .bomb and checked the status of this flight to see if it will tell me, however it only says " Terminal -- "

Could anyone be of assistance?
Thank You.