"I suppose you will go and stay with your brother and sister, Miss Dashwood, when they come to town," said Lucy, returning, after a cessation of hostile hints, to the charge. (Chapter 32)

I think JA is very clear how Lucy’s hostility towards Elinor shows through the thin veil of false friendship she pretends to. Chapter 32 has these two good examples but I would classify Lucy’s attitude at Barton as often mean with her deceitful stories and sly looks to see if they hit the mark—Lucy wanted to insure that she sunk any hope Elinor might have had for Edward. There was no sincerity in Lucy’s dramatized sentiments or overtures at friendship. Insinuating that Elinor lied about her plans, although cloaked as always in false sentiments of affection, is not actually trying to maintain friendly terms IMO—Lucy just relies on Elinor’s good manners to prevent her from branding Lucy the harpy she is.

"I should have been quite disappointed if I had not found you here still ," said she repeatedly, with a strong emphasis on the word. "But I always thought I should . I was almost sure you would not leave London yet awhile; though you told me, you know, at Barton, that you should not stay above a month . But I thought, at the time, that you would most likely change your mind when it came to the point. It would have been such a great pity to have went away before your brother and sister came. And now, to be sure, you will be in no hurry to be gone. I am amazingly glad you did not keep to your word."

Elinor perfectly understood her, and was forced to use all her self-command to make it appear that she did not. (Chapter 32)