EDIT: The direct Answer is: Yes, it is possible to run Elive, even without PAE, with 4 GB or more installed. But only a little less than 3GB would be used.
It is because of the address length. 32bit can only address roundabout 2,8 GB (3 GB barrier - Wikipedia)
But there is PAE (Physical Address Extension), as workaround.
But the MMU (Memory Management Unit) need to support it. Look at the manual for your motherboard, or the RAM compatibility list.
If >4GM RAM is supported, you'll just need to install a kernel with PAE support.
Check PAE on CPU Level:
grep -w pae /proc/cpuinfo
Check PAE on kernel level:
uname -r (There should be seen something like '-pae')
Search for supported kernels:
apt search linux-image |grep pae
grep CONFIG_X86_PAE /lib/modules/$(uname -r)/build/.config
- grep: search for pattern
- CONFIG_X86_PAE: searched pattern
- /lib/modules/$(uname -r)/build/.config: search path
- $(uname -r): at the moment loaded version
(Not tested, I'm on a 64bit Debian at the moment)