Why did C.S. Lewis name the lion Aslan and the Witch Jadis?

The name Aslan is Arslan in its Turkish origin and means 'lion'. It was used as a title borne or byname by medieval Turkish rulers. It is said that C.S. Lewis discovered the name in a footnote in Edward Lane's commentary/translation of The Thousand and One Nights also known as The Arabian Night's Entertainmentsand Lewis was inspired to use the name when he was in the Ottoman Empire(modern day Turkey) and was impressed with the Sultan's elite guards who were called Aslan due to their bravery and loyalty. The name Jadis on the other hand is incredibly difficult to find information on. One possible reason that Lewis used this name is that Jadis in the French language means 'days of old, yore, long ago'. This name could have been used because the British were familiar with the French and/or the meaning of Jadis refers to the witch's history, from the city of Charn in a whole different world from Narnia, as a person or ruler of old. Of course though this is just speculation.