according to those, it says ceci/cela should be used for all verbs except etre, pouvoir +etre and devoir+etre where it should be contracted so i assume it must be, unless it's wrong :-/
p.s. i severely doubt it's wrong seeing as http://en.wikipedia.org/wiki/The_Treachery_of_Images :) anybody care to wade in? is it such that when ce is used with etre or any of those other combinations it means something closer to it/he/she whereas ceci clarifies it back to "this"?
If you refer to a noun that you've already mentioned in the sentence, you use celui/celle/ceux/celles (masculine form, feminine formand both plurals). You can add ci and là to indicate where the the object is. Tu veux celui-ci ou celle-là?
If your refer to something you haven't mentioned in the sentence, you use ça/cela/ce/ceci. Ça is informal and means this here as wel as that there. Cela means that there. Ceci means this here. Ce is used in combination with être or pouvoir/devoir + être.
The 'here' is redundant in English. From https://www.grammarphobia.com/blog/2012/06/this-here.html : "As the Oxford English Dictionary says within its entry for “this,” the use of the demonstrative adjective “strengthened by here immediately following” is “dial. [dialectal] or vulgar.”