A 67-year-old woman with type 1 diabetes is admitted with community-acquired pneumonia and is not eating. She normally injects insulin glargine 24 units at night and insulin aspart with meals; her blood glucose concentration is 16 mmol/L and blood ketones are 0.2 mmol/L. The ward nurse asks how her insulin should be prescribed while she remains unable to eat. Which one of the following is the most appropriate plan?