أَوَ كُلَّمَا وَرَدَتْ عُكَاظَ قَبِيلَةٌ ...
Was it whenever a tribe came to ʿUkāẓ ...?
The example uses verbal presentation to evoke occurrences repeated on different occasions. ʿUkāẓ was a celebrated market and gathering place, and the arrivals of tribes suggest renewed events rather than a static description.
The expression does not mean that all arrivals took place within one indivisible instant. It indicates individual events recurring in appropriate temporal contexts. Verb form, repetition and the subject matter jointly shape its rhetorical effect.