إِلَّا إِذَا فَصَلَ، نَحْوُ: «ضَرَبْتُ الْيَوْمَ وَزَيْدٌ».
Translation: Except when a separating element intervenes, as in “I and Zayd struck today.”
Al-yawma is inserted between the attached subject and the coordinated noun. In this source example, the separate pronoun anā is not required.
The separation changes the reinforcement requirement, not Zayd’s nominative case.