How to frame a question?

If someone says: “I was in the hospital” OR “I had an operation”.

What are the different ways to ask the question about the time she was hospitalized?

Some possible questions:

-When were you in hospital?
(You ask about the period he was in hospital; you presume he is not in it anymore.)

-When were you admitted to hospital?
-When were you taken to hospital?
(You ask about the moment he was taken to hospital; you presume he is not there anymore.)

-Since when have you been in hospital?
(You ask about the moment he was taken to hospital; you presume he is still there.)

-When did you have the operation?

Some possible questions:

-When were you in hospital?
(You ask about the period he was in hospital; you presume he is not in it anymore.)

What if I ask: When were you in the hospital?

Thanks for you prompt reply, could you refer me somewhere I can learn more about framing questions in all possible situations.

Yes, “the” is fine: with some words, the article is left out in Britain; in America, the article is usually kept. “To the hospital” is American; no article is British.

On this page, scroll down until you see “Questions” and “Tag Questions”:
englishclub.com/grammar/verbs.htm