No, you won't be able to use gparted to resize JHFS+/X. You'll need to use diskutil resizevolume from command line to do that. I'm not aware of a GUI tool (other than Boot Camp and it is very constrained on what it will let you do).
Since you have Lion, your partitions are:
EFI System
Mac OS
Recovery HD
Windows
So when you resize Mac OS, you will create a gap of free space between Mac OS and Recovery HD. You'll need to slide it over. dd can do this as a sector copy and then relocate, using gdisk to change the GPT partition table to account for the change. But maybe gparted can do only a move without resize, in-place without needing extra space to copy it elsewhere first.
Once you slide Recovery HD back so that it butts up with Mac OS, you'll have free space in front of the Windows partition. You can use gparted to resize/move such that you change the start block of the Windows NTFS partition to the new start of free space created, and resize to fit in that whole space.
Last, the disk will have reverted to GPT only with a protective MBR, which is an MBR with a single 0xEE entry. This will prevent Apple EFI from initiating the CSM-BIOS and booting Windows. So you'll need to create a new hybrid MBR, which is pretty non-obvious. Again gdisk can help with this. The way I do it is I only add the Windows partition to the hybrid MBR and stuff all the other GPT partitions (EFI, Mac OS, Recovery HD) into the MBR 1st partition 0xEE protective entry. Remember to mark that Windows partition bootable in the MBR as well - gdisk asks if it should set this flag.
It should work. I've done it many times, just not with gparted. But fraught with peril because it's possible to make one mistake and hose the whole process. And all data. So just be REALLY careful.
Equally important to the backup, is a screen shot (or something) of the existing GPT entries. I use:
gdisk -l /dev/disk0
and then print out that table, if you mess up the GPT, the data on the disk is NOT HURT. But to get access to it, you must have valid numbers to generate a whole new GPT if necessary.
Also, if FileVault 2 is enabled, you have to disable it, decrypting your disk, before it's possible to resize JHFS+/X. This I have not done, so I don't know if upon decryption if it remains a Core Storage logical volume, or if it's restored to being a normal volume. If it's normal, you can resize. If it's still Core Storage I don't think it's resizable.