I find this match up goes much easier if you are more on the offensive than defensive. NOt necessarily blindly swinging you massive sword around like Zaraki Kenpachi from Bleach but simply not jsut waiting for arakune to attack you.
The best time to be defensive is when you are cursed which is THE most difficult thing since you have to simultaneously pay attention to both the entire screen as to watch out for bees and watch where arakune is going and where you are in case of a grab,
I personally have won more matches against arakune being cautiously aggressive from the get go n then trap him in the corner and molest him without remorse. While he is low to the ground enough for haku-men to approach him from the air I find 2c to be the msot effective since it most likely lands a counter hit allowing him to be sent into the corner for the molestation to begin until he somehow finds a way to teleport.
I have a cousin who uses arakune so this match up is much easier for me than those who dont have someone regular to play against. Which is why I wish I knew someone who uses Nu so I can build experience against her since matches against skilled Nu' last roughly 30 seconds with me landing one combo on them.