When one circumvents the idea of an infinite regress by postulating God not having needed a cause, as he was eternal, is this sensical?

I was listening to a debate with William Lane Craig and he seemed to imply something to that effect; namely that God is the best explanation for the origin of the universe by virtue of the fact that all effects need causes, and as there wasn't much else around (by definition) prior to the inception of the universe, hypothesizing a God is the most reasonable- and perhaps a necessary- position.

Typically this would seem to be a silly claim, as one could revert to the problem of infinite regress, but if one claims that God is exempt from the cause and effect process because he did not come into being (he is not an effect), as he is eternal, how would a religious critic answer this? It seems to make sense to me intuitively.. if something doesn't come into being, i.e., if there is no effect, we needn't look for a cause. If it is true God is eternal, wouldn't he by definition not need a cause?

I've been an atheist for some time now, not sure why this never occurred to me.. I was familiar with the infinite regress problem but what if someone simply asserts that God doesn't need a cause because he is eternal?

Thanks