I'd like to say something like "Then, we have the question: why did this happen?" What is a proper way to say this using the phrase "The question then arises..."? Is it "The question then arises as to why this happened."? If this is correct usage, are there other continuations of this phrase (i.e. "The question then arises") that I could use?
The phrase means "this brings up the question", and sounds fine to a native English speaker. If you Google, the phrase the question then arises is usually used as follows (all of these are from Google results):
The question then arises, "How do we calculate the amount of power dissipated by a resistor?"
The question, then, arises: who is correct?
The question then arises as to what sort of change happens after a thing is destroyed?
You can use the phrase the question then arises in the same way that you would use then we have the question. You could write:
The question then arises: why did this happen?
The question then arises, "Why did this happen?"
The question then arises as to why this happened.
The last example is a bit harder to understand, so I would recommend the first two over the third. You could use "the question then arises" with most questions that happen to arise--there aren't any exceptions which I can think of.
You have two options.
1. Put a colon ":" after the phrase, then state the question:
The question now arises: What about the millions of dollars in currency-conversion fees Canadian investors have paid since 2001 to the banks?
Sometimes a comma or dash is substituted for the colon; however, if you are a grammar stickler, you will not want to use these:
The question now arises, am I aught besides?
The question now arises - how do you use crystal as a Sunstone?
2. Temporarily move the "now arises" to the end of the sentence, form it that way, and put the "now arises" back in.
The question of where Lidge falls into this jumbled Phillies pen now arises.
The question now arises of where Lidge falls into this jumbled Phillies pen.
The question as to why this happened now arises.
The question now arises as to why this happened.
(Examples taken from the first page of a google search.)