This mainly depends on the cause of the scrub, it seems.
I went back through Ariane 5 launches. When a scrub was caused by a technical problem, it'd take several days or weeks to make another attempt. The vehicle has to be drained of fuel, rolled back to the assembly building, failure analysis etc.
When the cause is external (weather, nimrods driving their boat into the exclusion zone), Arianespace has done launches on the next day.
And why the next day? For many orbits, there's only one time of day when that orbit is above the launch site and reachable. So for any launch where the scrub and retry would put you outside of the launch window, you have to wait 24h to try again.