＊This grammar is used to indicate time when one faces something formal. The compound particle is primarily used in written Japanese. When a verb precedes it, the verb is often a Sino-Japanese する verb, as in example #6306.
＊The tense of the verb before に当たって;に当たり is always nonpast regardless of the tense of the final predicate. In this way, an incomplete aspect of an action is indicated by the verb. This is why the phrase can be translated into English as 'before' or 'prior to.'