Albert Barnes Commentary Lamentations 2:1

"How hath the Lord covered the daughter of Zion with a cloud in his anger! He hath cast down from heaven unto the earth the beauty of Israel, And hath not remembered his footstool in the day of his anger." — Lamentations 2:1 (ASV)

How ... - Or, “How” does “אדני 'ădonāy cover.” He has cast down etc. By God’s footstool seems to be meant the ark. See Psalms 99:5 note.