@triantares is 100% right, but I want to go a little deeper into the analysis. Take a look at the package name. skypeforlinux-64.deb means it is for 64bit architecture.
But to be sure, let's open the package (the option an uppercase i, not lowercase L), than compare to the system.
lupus@zoe:~$ dpkg -I skypeforlinux-64.deb |grep Architecture
Architecture: amd64
lupus@zoe:~$ dpkg --print-architecture
amd64
Here it matches.
You're able to run 32bit applications on a 64bit system. Not the other way around.
The solution: Use the Elive - Beta Download, it is 64Bit.
It won't help, since you've got the same issue, but out of personal interest:
Are you sure you want to install Skype? Most features of Skype are available in the modern teams. There are only a few situations, I can imagine Skype should be used over teams. And none of them allows the use of Linux.
