"Hi, I have following question. Blah blah" is fine.

But

  - Hi
  - <2 min pause and typing icon appears. I wait doing nothing or get to work>
  - I have a question about X.
  - <4 min pause and typing icon appears, as person struggles to write it. I wait doing nothing or get to work>

And only after you get question. That was too much waiting idle, being interrupted and still not communicating.