The phrase "an important question when" is correct and usable in written English.
It can be used to introduce a significant inquiry that arises in a specific context or situation.
Example: "An important question when considering climate change is how we can reduce our carbon footprint effectively."
Alternatives: "a crucial question when" or "a significant question when".
Lewis asked an important question when we spoke: "This is a multidecade movement.
This was an important question when this was first performed two years after the French revolution - and now.
Meanwhile, for the rest of us, the deal raises an important question: When do manufacturing subsidies make sense, and how big should they be?
Criticism of explorer Benedict Allen, rescued in Papua New Guinea, raises an important question: when is it legitimate to travel to remote communities?
In a recent article on Comment is free, Mark Seddon posed an important question when he asked why David Cameron has not spoken up for his "new great friend" in politics, the ousted president of the Maldives, Mohamed Nasheed.
The Senator and I chewed over an important question: When does a contractor become an employee?
JL: I always like to ask designers and architects, and to me it seems an important questions when you design or build, what is your favourite force of nature?
One of the outstanding issues in H-cluster structure over the past decade has been the identity of the bridgehead atom in the dithiolate ligand, an especially important question when attempting to define the origin of this molecule.
These are all important questions when looking at creating a savings plan for children.
Whether enhanced RAF kinase activity influences these later changes is an uncertain but important question when considering BRAF and RAF kinases as therapeutic targets for patients with undifferentiated forms of thyroid cancer.
I had an opportunity to consider this important question when, earlier this year, I led a debate with four professors from the University of California, Berkeley, who were experts in artificial intelligence, neuroscience and psychology.
