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No record of his apprenticeship has been found.
He entered a mark at Goldsmiths’ Hall in 1720 as a free Clockmaker from Porter Street on the corner of Newport Alley.
He signed a bond in 1729 as a thirty three years old widower and Watch Case Maker from St Ann, (Soho), Westminster to marry, with the consent of her father Augustin (Grimwade p.474), seventeen years old Hester Courtauld.
Abraham Ferron (Grimwade p.288) son of Louis Ferron watch maker of St Ann, Westminster in 1725, Augustin, son Augustin Courtauld, goldsmith St Martin in the Fields, in 1732, Lason (Jason?) Ribouleau from Portsea, Hampshire in 1735 and Thomas Venn (Grimwade p.323, 688) of Westminster in 1752 all signed to be apprentices of Stephen Goujon/Gujeon (sic) of the Clockmakers Company and of St Ann’s parish, Westminster.
Samuel the son of Stephen Goujon applied for freedom by patrimony in the Clockmakers Company in 1763/4.

MCB wrote:Lason (Jason?) Ribouleau from Portsea, Hampshire in 1735....

There are a number of primary documents for a Lason Ribouleau, and none that I have been able to locate that refer to a Jason Ribouleau. Among those documents for Lason are the indenture contract Mike has mentioned and a couple of apprentice duty payments that all refer to Lason as a clockmaker or clockmaker's apprentice. I can see where the signature on Lason's indenture contract leaves a little room for error with the first letter of his first name because of uneven ink flow when it was written, but it is still not difficult to interpret the letter as an "L." Additionally the mark shown in Grimwade, no. 1962, for "Jason" Ribouleau resembles "L-R" and not "J-R" to me. I'd say Mike was right to question whether Lason and Jason Ribouleau were the same person and that Lason is correct.