Thanks both.
The Quebec quote is not suitable because we are only talking about Que si at the beginning of a sentence. The que in the Quebec quote is just a conjunction.
Here is the quote I am trying to understand:
“Dans la langue litteraire, que précède parfois la conjonction si au commencement d’une phrase; on lie ainsi plus etroitement que par le simple si ce qu’on va exprimer à ce qui précède (tournure due probablement à l’imitation du lat. quod si)…” (Section 972 of Le Bon Usage)
In the literary language, que precedes sometimes the conjunction si at the beginning of a phrase; one ties thus more tightly than by the simple si what one is going to express to what precedes (phrase probably due to the imitation of the latin quod si)…
I don’t know whether “ce qui précède” (what preceedes) refers to X or to P.
Now they follow the passage quoted with four examples. All are just conditionals. That would seem to indicate that the Q gets tied more tightly to the P since they don’t include any X’s. The first is just: If (Que si) this wolf attacks, hit him in the jaw. But I don’t see what is so tight here. Nor do I have any idea what it would be to tighten a conditional. Nor do I understand the apodosis of a conditional to be that which one is going to express; rather the whole thing, protasis plus apodosis, is what one expresses. So, I started thinking well maybe the meaning was more like “Given that, if”, “Given what we have just said, if”, “In light of that, if”, etc. Something along those lines. There I could see some tightening. Now unfortunately Grevisse just spends two short paragraphs on this phrase, but the author that I am reading uses it enough that it has started to bother me.
Now perhaps the Cicero quote is promising. Translating Que si by “Even if” perhaps does reveal the nature of the tightening. But it doesn’t fit the wolf example. Even if that wolf attacks hit him in the jaw?? It does better with the other examples, however.
I think I’m mistranslating the wolf example. It seems it is more like, “if the wolf is expecting it, hit him in the jaw.” There, “even if”, would be good. But French already has an expression for even if: même si. And Grevisse doesn’t mention it. Which seems unimagineable. So I’m still at a loss.