Learn Dutch: In elk geval is dit handig. - In any case this is handy.

While voor het geval (dat) means "in case" (referring to a hypothetical situation), in elk geval means "in any case" or "anyway". They both use the noun geval (case or situation), but in elk geval states a fact that is true regardless of the circumstances, rather than setting up a condition.

Why is the verb 'is' placed before the subject 'dit'?

Because of the verb-second (V2) rule. Since the phrase In elk geval takes up the first position in the sentence, the verb is must come second. This pushes the subject dit to the third position.

Why doesn't 'elk' get an -e at the end here?

The noun geval is a neuter word (het geval). When you use elk (each or every) with a singular het-word, it does not get an -e ending. If you were talking about a de-word, it would be elke.

Can I use 'ieder' instead of 'elk' in this phrase?

Yes! You will hear in ieder geval very frequently in spoken Dutch. It means exactly the same thing: "in any case" or "at least".