My first reaction would be IAS 39 and not IAS 23 unless the case is that you want to capitalize these costs as part of an asset cost. The latter is not clear from your description. I would treat the arrangement cost as an adjustment to the effective interest of the loan.
Met vriendelijke groet,
I agree: IAS 39 with cost as part of the effective yield and the hedge defined as a cash flow hedge.
Please follow IAS39 for accounting of this hedge.
The IAS23 is only about capitalisation of borrowing cost to asset (ie. under certain conditions you are allowed to capitalise interests from this loan prior to capitalisation of the assets).
I am not sure if the loan was drawn to finance asset development or for other purposes.