Hey CJK,
Good question - You need to hit 10,000 LIFETIME points. If you earn 5000 pts, spend 5000 points, and earn 5000 more points, you will only have 5000 points in your account, but your LIFETIME balance will be 10,000, and you will qualify for Elite Membership. Feel free to spend your points along the way, no need to save them for your Elite status.
Have a great week!
// L