In Chapter 1, when Mrs Bennet is trying to persuade her husband to visit Mr Bingley, she says,

"Sir William and Lady Lucas are determined to go, merely on that account, for in general, you know, they visit no new-comers."

I find this hard to believe, of Sir William at least, considering what the narrator says of him in Chapter 5

"he could think with pleasure of his own importance, and, unshackled by business, occupy himself solely in being civil to all the world. For, though elated by his rank, it did not render him supercilious; on the contrary, he was all attention to everybody."