The base text uses “before zawal”. Later Hanafi authorities, including Fath al-Qadir and Radd al-Muhtar, prefer “before al-dahwah al-kubra”: the midpoint of the interval from true dawn to sunset.
This legal midpoint usually occurs earlier than astronomical midday/zawal. The learner should not treat “just before Dhuhr” as a safe practical deadline. The original author’s words are preserved while the juristic qualification is disclosed.