لَوْ تَأْتِينِي فَتُحَدِّثَنِي
If only you came and spoke with me.
The subjunctive in fa-tuḥaddithanī is commonly explained by an implied an after the causative fāʾ, because the clause answers a wish. The rule does not transfer indiscriminately to every conditional law.
Comparative review
ParticleTypical rhetorical use
ليتPrimary marker of wishing
هلInterrogation used as a wish
لوConditional form used for wishing
هلّاExhortation or past reproach
لولاExhortation or reproach