Learn French: Elle va dévoiler la ruse, pour peu qu'on lui pose la question. - She is going to unveil the ruse, provided that we ask her the question.

Pour peu que is a conjunction that expresses a minimal condition. It usually translates to "provided that," "if only," or "so long as." Here, it implies that it takes very little effort—just asking her the question—for her to give up the trick.

Is pose in the subjunctive here? It looks identical to the present indicative.

Yes, it is in the subjunctive! The expression pour peu que always triggers the subjunctive because it sets up a hypothetical condition. Since poser is a regular -er verb, its subjunctive form for il/elle/on (qu'on pose) happens to share the exact same spelling as the present indicative.

Why do we use the indirect object pronoun lui instead of the direct object la?

In French, you don't "ask someone," you "pose a question to someone" (poser une question à quelqu'un). Because of that invisible à in the structure of the phrase, we must use the indirect object pronoun lui (meaning "to her" in this context) rather than the direct object la.

What is the literal meaning behind the verb dévoiler?

It literally means "to unveil." It is built from the noun le voile (the veil) and the prefix dé-, which indicates removing or undoing an action. It's a great descriptive verb for revealing a secret or a ruse.