Simple RAW for 5e V: The Disadvantage Strikes Back

[Seliven]

Q367
Does spirit shroud alter spells with spell attacks to deal radiant damage, so that a casting of eldritch blast affected by spirit shroud triggers the celestial warlocks radiant soul ability? (provided the target is within 10 feet and radiant damage is chosen)

[...]Until the spell ends, any attack you make deals 1d8 extra damage when you hit a creature within 10 feet of you. This damage is radiant, necrotic, or cold (your choice when you cast the spell).[...]

[...] when you cast a spell that deals radiant or fire damage, you add your Charisma modifier to one radiant or fire damage roll of that spell against one of its targets.