No, the Canon PowerShot V10 is not compatible with the Lexar Professional CFexpress Type A Gold 256GB.
Canon PowerShot V10 has a microSD-only card slot (no CFexpress support of any type). Its own compatible-cards manual page confirms only microSD/microSDHC/microSDXC card compatibility -- CFexpress Type A uses a physically different, much larger connector and cannot be inserted into a microSD slot.
What works instead
See all compatible camera for the Canon PowerShot V10 →“microSD / microSDHC / microSDXC memory cards SD speed class compatible UHS speed class compatible UHS-I compatible”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)