Yes and no. The regulations on the 90 day waiting period, orientation period, and 1,200 Hour Rule are not specific to small employers.
However, the Departments point out that an employer that has a one-month orientation period followed by a 90 day waiting period may not comply with the employer mandate.
Here is the final rule on orientation periods: https://www.federalregister.gov/documents/2014/06/25/2014-14795/ninety-day-waiting-period-limitation
From the Final Rule:
Compliance with these final regulations is not determinative of compliance with section 4980H of the Code, under which an applicable large employer may be subject to an assessable payment if it fails to offer affordable minimum value coverage to certain newly-hired full-time employees by the first day of the fourth full calendar month of employment.
For example, an applicable large employer that has a one-month orientation period may comply with both PHS Act section 2708 and Code section 4980H by offering coverage no later than the first day of the fourth full calendar month of employment.
However, an applicable large employer plan may not be able to impose the full one-month orientation period and the full 90-day waiting period without potentially becoming subject to an assessable payment under Code section 4980H.
For example, if an employee is hired as a full-time employee on January 6, a plan may offer coverage May 1 and comply with both provisions. However, if the employer is an applicable large employer and starts coverage May 6, which is one month plus 90 days after date of hire, the employer may be subject to an assessable payment under Code section 4980H.