Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
The scholars differed in regard to the interpretation of Dulook.
Some of them interpreted it as follows: "It is when the sun is at its meridian." This is narrated by Omar, Ibn Omar, Abu Hurairah, Ibn Abbas and others.
However, others interpreted it as sunrise. This is narrated by Ali, Ibn Mas'ood, Ubai, and in one narration of Ibn Abbas, and others.
Some others interpreted it to be: "When the sun passes its meridian until sunset." This is narrated by Qatada and Al-Akhfash.
Allah knows best.