Oh, dear, yes! Lydia is culpable! I can not see Elizabeth, for instance, even at the height of her admiration for Wickham running off with him! Lydia is a rash fool, and came within a hair's-breadth of ruining her own life and her family's standing.

I was only saying that Wickham saw her weakness and used it. I doubt Lydia has the power of 'insisting' on anything to such a selfish, unprincipled man. In Ch. 51: Elizabeth decides:

She had scarcely needed her present observation to be satisfied, from the reason of things, that their elopement had been brought on by the strength of her love rather than by his; and she would have wondered why, without violently caring for her, he chose to elope with her at all, had she not felt certain that his flight was rendered necessary by distress of circumstances; and if that were the case, he was not the young man to resist an opportunity of having a companion.