My first pass through the internet revealed that the name was derived from French terms as follows:

"This 1950's patented term is an acronym for ace TA te de cellu LOS e EL abore (Elaborate Cellulose Acetate)."

Cellulose acetate (CA) followed the development of cellulose nitrate (Celluloid) and was less flammable than Celluloid. CA melts easily and also dissolves easily in many industrial solvents. Most of the commercial uses started up after WWI (1917) although the chemical itself was known back in 1865. CA was/is used for film, fibers, and other plastic articles like buttons, eyeglass frames, and even the original Lego bricks (1949 - 1963).

To make Talosel, it looks like colored additives and maybe fillers were used to create a CA paste or dough that was made into sheets or free-form shapes. A lot of the Talosel designs has small mirrors embedded into thicker pieces.

Also -seems the spellings with one s and two s's are used interchangeably.