Elbert went immediately to George Washington's headquarters in the north. General Washington was elated to accept Elbert's services, and at the Siege of Yorktown in 1781, Elbert was given command of a brigade. While at Yorktown, he made a lasting friendship with a young French general, the Marquis de Lafayette. This friendship continued after war's end, and these two men maintained a friendly correspondence for many years. Such was Elbert's admiration for Lafayette that he named one of his sons after him.