Skylark = l'arc-en-ciel

"A sensitive plant, what?"

"Exactly. You know your Shelley, Bertie."

"Oh, am I?"

-- P. G. Wodehouse, The Code of the Woosters

The French for "rainbow" is l'arc-en-ciel -- or, to translate partially, l'arc-in-sky. This obviously corresponds perfectly with the English word skylark. Shelley, in his poem To a Skylark, relates that bird to the rainbow.

What thou art we know not;

What is most like thee?

From rainbow clouds there flow not

Drops so bright to see

As from thy presence showers a rain of melody.

I've got nothing else to say about this at this point. I simply note it in anticipation.