Minimal condition conjunction (pour peu que)

Planning a surprise party requires extreme stealth. You will need a good ruse, some clever diversions, and the ability to pretend nothing is happening while you secretly prepare.

We secretly hired the caterer for the surprise.
Nous avons secrètement engagé le traiteur pour la surprise.
Do not unveil the gift and pretend to work.
Ne dévoile pas le cadeau et fais semblant de travailler.

The minimal condition: pour peu que

When coordinating a complex surprise, it sometimes takes only one tiny mistake to ruin everything—or one small action to ensure success. To express this "minimal condition," use the conjunction pour peu que.

It translates to "provided that," "if only," or "if [someone] so much as [does something]."

Because this conjunction sets up a hypothetical condition, pour peu que must always be followed by the subjunctive mood.

The caterer is going to be ready, provided that we give him some time.
Le traiteur va être prêt, pour peu qu'on lui donne du temps.
The diversion is going to succeed, provided that you distract him.
La diversion va réussir pour peu que tu le distraies.

Notice how the subjunctive forms donne and distraies immediately follow the conjunction. The rule applies just as strictly to irregular subjunctive verbs like être, avoir, and voir:

He is going to arouse suspicion, provided that he is talkative.
Il va éveiller les soupçons, pour peu qu'il soit bavard.
The diversion works provided that you have a pretext.
La diversion fonctionne pour peu que tu aies un prétexte.
He will become suspicious if he so much as sees this garland.
Il deviendra méfiant pour peu qu'il voie cette guirlande.