William Shakespeare ~ Sonnet 149

Canst thou, O cruel! say I love thee not,
When I against myself with thee partake?
Do I not think on thee, when I forgot
Am of myself, all tyrant, for thy sake?
Who hateth thee that I do call my friend?
On whom frown'st thou that I do fawn upon?
Nay, if thou lour'st on me, do I not spend
Revenge upon myself with present moan?
What merit do I in myself respect,
That is so proud thy service to despise,
When all my best doth worship thy defect,
Commanded by the motion of thine eyes?
But, love, hate on, for now I know thy mind;
Those that can see thou lovest, and I am blind.

&

PS As far as I know this is the only time WS ever uses the term lour'st (meaning scowl?) have you ever seen it used elsewhere?