Very nice show indeed.
Good rythm, good contrasts, nice alternance of comedy and deeper plots.

Regarding Eclair Tonnerre or Lightning Thunder, she is exactly that. She's Flashy, comes very quickly, sounds dangerous... but in the end has little effects on the world.
It's also nice she's named like this, as Haruhi is afraid of Lightnings and Thunders...

I was a bit afraid this show would be a bit too gay, but in fact it was very light (except for Haruhi's father...) and amusing all the way.

I LOLED a lot with the reference to the Weapons of Mass Destruction... when the shota boy shouldn't ever fight at 100% in public, to prevent Japan from being attacked by the UN for having weapons of mass destruction