Yes, the Tradition of Sunday as a day or worship for many Christians is based on the day of resurrection. It is not based on a belief though that the resurrection took place on some first day, but rather on the fact that the story has it happening the day after the Sabbath.
It would be more accurate to say that many Christians feel that Jesus resurrection began things and so is a new beginning each week.
How a Calendar is arranged is a business and aesthetic decision, and is up to the individual. Sunday is still Sunday, regardless of where you start some arbitrary calendar. Look at the Yahoo Calendar application which is pretty typical.
I can start the week on any day I choose.
Calendars are arbitrary creations of man.
Aslan is not a
Tame Lion