To keep your arrangement of 10 pcs white delphinium in a glass vase looking fresh and beautiful, here are some care tips:

1. **Watering**: Ensure the vase is filled with clean, lukewarm water. Change the water every two days to prevent bacterial growth. Delphiniums are thirsty flowers, so check the water level daily and top up as needed.

2. **Trimming**: Trim the stems at a 45-degree angle before placing them in the vase. This allows for better water absorption. Remove any foliage that will be below the waterline to prevent bacterial contamination.

3. **Location**: Place the vase in a cool spot away from direct sunlight and heat sources. Delphiniums prefer cool environments, so avoid placing them near radiators or air vents.

4. **Cleaning**: Remove any wilted or spent blooms promptly to encourage new growth. Gently wipe the leaves with a damp cloth to remove dust and debris.

5. **Support**: Delphiniums have tall, delicate stems that may require support. Use floral tape to create a grid pattern over the mouth of the vase, which will help support the stems and keep them upright.

6. **Avoiding Ethylene**: Keep the delphiniums away from ripening fruits and vegetables, as they produce ethylene gas, which can cause the flowers to deteriorate more quickly.

7. **Enjoyment**: Take time to admire and enjoy your beautiful arrangement of white delphiniums. With proper care, they should last for about a week or more.

By following these care tips, you can ensure that your arrangement of white delphiniums remains fresh and vibrant for as long as possible, bringing beauty and elegance to your space.