Siman 347
Presented here for study, not as a practical ruling. The Shulchan Aruch rules by Sephardi custom, the Rema's glosses by Ashkenazi custom, and the Kitzur follows Ashkenazi custom. For a practical question, ask your rabbi.
א מִי שֶׁמֵּת לוֹ מֵת לִפִנֵי שְׁלֹשִׁים יוֹם הַסְמוּכִים לָרֶגֶל, לֹא יִסְפְּדֶנּוּ מִשֶּׁיִּכָּנְסוּ שְׁלֹשִׁים יוֹם הַסְמוּכִים לָרֶגֶל, וַאֲפִלּוּ יֵשׁ לוֹ הֶסְפֵּד בְּלֹא זֶה, כְּגוֹן שֶׁמֵּת לוֹ מֵת בְּתוֹךְ שְׁלֹשִׁים שֶׁמֻּתָּר לְסָפְדוֹ, וַאֲפִלּוּ מֵת עֶרֶב הָרֶגֶל, אָסוּר לְהַסְפִּיד עִמּוֹ עַל הַמֵּת שֶׁמֵּת לוֹ לִפְנֵי שְׁלֹשִׁים יוֹם קֹדֶם הַמּוֹעֵד.
1 One who suffered a bereavement prior to thirty days before a Festival, should not make a lamentation for him from [the time] that the thirty days before the Festival begin. [This applies] even if he has to make a lamentation [in any case] without this, e.g., [if] he suffered [another] bereavement within the thirty days [of the Festival], for whom it is permissible to make a lamentation, even if he died on the eve of the Festival, [nevertheless], it is forbidden to make a lamentation along with him for the bereavement that he suffered before thirty days prior to the festive season.
ב מִי שֶׁבָּאָה לוֹ שְׁמוּעָה בְּתוֹךְ שְׁלֹשִׁים יוֹם קֹדֶם הָרֶגֶל, נִרְאֶה לִי שֶׁמֻּתָּר לְסָפְדוֹ, אַף עַל פִּי שֶׁהִיא רְחוֹקָה.
2 One who received tidings [of death] within thirty days before the Festival, it seems to me that it is permissible to make a lamentation for him, although it is [already now] distant [tidings].
ג מַה שֶּׁאָנוּ נוֹהֲגִין בְּתַשְׁלוּם הַשָּׁנָה לְקוֹנֵן וּלְהַזְכִּיר נְשָׁמוֹת, נִרְאֶה לִי אֵינוֹ בִּכְלַל זֶה וּמֻתָּר לַעֲשׂוֹתוֹ סָמוּךְ לָרֶגֶל.
3 Our accepted practice upon completion of the [first] year to bewail and to memorialize the souls [of the dead], seems to me, is not included in this principle, and it is permissible to do so close to the Festival.