"Ble bydd e nos Iau?"

Translation: Where will he be on Thursday evening?

[MatthewSke1]

Why would "bydd" lenite when it's at the start of the sentence in a question, but not after "Ble"?

[EllisVaughan]

Because there would never have been a particle before it for it to mutate.

[PaddyDaley1]

We don't change the verb to the question form after "when?", "where?", "why?" and "how?". e.g. in the present tense we say "Ble mae e?" not "Ble ydy e?".

[pambirtill]

Sometimes nos is used for evening - I've seen it elsewhere in the course - so should "where will he be thursday evening" also be allowed?