Allah is mentioned by Name in Hindu Scriptures

The Word “Allah”, which refers to Almighty God in Arabic, is also mentioned in

Rigveda Book 2 hymn 1 verse 11
Rigveda Book 3 hymn 30 verse 10
Rigveda Book 9 hymn 67 verse 30

There is an Upanishad by the name ALO Upanishad.