“Who turned off the lights?”

Question

Who turned off the lights?
Who are you?

Why do the words in those questions have a different order than the following questions?

Does she like ice cream?
Where do you live?
Where do you come from?
Where are you?

Answer 1

So, you are asking why we say "who turned off the lights?" instead of:

*Who did turn off the lights?

Or something along those lines.

The difference is in whether the WH-word (e.g. who/what/when/where/why/how) is the subject or not. If it is the subject, then you just put the Wh-word where you would have put the subject, and nothing else about the sentence changes. But, in any other case, we get the verb movement and possible introduction of "do/does" into the sentence that you are expecting:

What did you turn off?

In this case, "what" is the object of the sentence.

When did you turn off the lights?

In this case, "when" is an adverb, again not the subject of the sentence.

If you want to know the real deep answer to why it patterns this way, there is an area of syntax called WH-movement that deals with these kinds of things.

Answer 2

As far as "Who turned off the lights?" is concerned, I think turned off has an infinitive off that ought not to be split from the verb turned. Hence you have the whole phrase in one place. [Btw, some people do come up with "Who offed the lights?"]

@Kosmonaut: "something along those lines" might be "Who has [/had] turned off the lights?"